Control for scraper bowl to remove load from hydraulic circuit when bowl is raised



Nov. 25, 1969 w. H. EIGER 3,479,757

CONTROL FOR SCRAPER BOWL TO REMOVE LOAD FROM HYDRAULIC CIRCUIT WHEN BOWL IS RAISED Filed April 26, 1967 2 Sheets-Sheet 1 :1 BY zZ/ZwX/ELr Nov. 25, 1989 w. H. EIGER 3,479,757

CONTROL FOR SCRAPER BOWL TO REMOVE LOAD FROM HYDRAULIC CIRCUIT WHEN BOWL IS RAISED Filed April 25. 1967 2 Sheets-Sheet 2 IN VENTOR.

nited States Patent CONTRUL FOR SCRAPER BOWL TO REMOVE LOAD FROM HYDRAULIC CIRCUIT VVHlEN BOWL IS RAISED William H. Eiger, Eastlake, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Apr. 26, 1967, Ser. No. 633,841 Int. Cl. E02f 3/85 lU.S. Cl. 37-129 2 Claims ABSTRACT OF THE DISCLOSURE A scraper bowl control mechanism for raising and lowering the bowl between a carry position and a dig position. The mechanism including a hydraulic cylinder and lever means having a portion thereof adapted to be located in a position where the weight of the forward end of the bowl is transferred from the hydraulic cylinder to the scraper structure so as to relieve the hydraulic circuit from any load when the bowl is in a raised-carry position.

The typical scraper has a tractor connected to a trailing bowl by a drawbar which supports control mechanism that permits the bowl to be located in a raised-carry position or a lowered-dig position. The control mechanism takes various forms; however, in most cases, one or more hydraulic jacks are used for moving the bowl between the aforementioned positions. At times, the jacks are connected to associated levers hinged at the forward ends thereof to the drawbar and connected at the rear to links which, in turn, are secured to the bowl. In other arrangements, the jacks may be connected directly to the bowl without the use of any intermediate members. Irrespective of what form the control mechanism takes, however, none are completely satisfactory because the jacks are required to support the bowl when the latter is in a carry position. As a result, the hydraulic circuitry leading to the jacks is often subjected to shock loads which can damage the jacks and/ or cause rupture of the lines.

Accordingly, the objects of the present invention are to provide a scraper bowl control mechanism having an operating jack that is relieved from any load when the bowl is in the raised-carry position; to provide a bowl operating mechanism having a lever that rotates to an overcenter position when the bowl is moved from a lowered-dig position to a raised-carry position; to provide a control mechanism for a scraper bowl that transfers the weight of the bowl from the bowl operating jacks to the drawbar; and to provide a scraper bowl control device having a bowl-supporting lever that is movable about its pivotal connection with a drawbar to a position wherein a portion of the lever rests on the drawbar and thereby transfers the weight of the bowl from the operating jack to the scraper structure when the bowl is in a carry position.

Other objects and advantages of the present invention will be more apparent from the following detailed description when taken with the drawings in which:

FIGURE 1 is an elevation view of a scraper bowl incorporating a bowl control mechanism made in accordance with the invention;

FIGURE 2 is an enlarged sectional view of the bowl control mechanism;

FIGURE 3 is a view taken on line 3-3 of FIGURE 2; and

FIGURE 4 is a plan view of the scraper bowl shown in FIGURE 1.

FIGURE 1 shows a scraper bowl having the forward end thereof supported by a drawbar 12 which in 3,479,757 Patented Nov. 25, 1969 turn is connected to a steering and coupling member 14 normally associated with a tractor, not shown. The rear end of the scraper bowl 10 as well as the coupling member 14 are provided with the usual ground-engaging wheels 16 which permit the unit to be supported and transported in a conventional manner. As seen in FIG- URE 4, the drawbar 12 comprises a pair of rearwardly diverging structural members 18 and 20, the rear ends of which are rigidly secured to a transversely extending torque tube 22. The opposite ends of the torque tube 22 support pull arms 24 and 26, the rear ends of which are respectively connected to intermediate side portions of the scraper bowl 10 by ball-and-socket joints 28 and 30. As is well known, this form of scraper construction permits the bowl to be moved about a horizontal axis passing through the joints between a raised-carry position and a lowered-digging position as shown in FIGURE 1 in full lines and the phantom lines, respectively. For purposes of moving the scrape-r bowl 10 between these positions, a control mechanism 32, according to this invention, is provided on the drawbar 12 and located between the members 18 and 20.

As seen in FIGURES 2, 3, and 4, the control mechanism 32 includes a U-shaped lever or bellcrank 34 comprising a pair of identical and laterally spaced legs 36 and 38 integrally formed with a transversely extending base section 40. The lever 34 is supported on the torque tube 22 for rotation by a pin 42 press-fitted in the legs 36, 38 and journaled within a pair of ears 44, 46 which are rigidly connected to the torque tube. Each leg 36, 38 of the lever 34 is of triangular shape in side view and has axially aligned pivotal connections 48 and 50 for respectively joining the upper ends of links 52 and 54 to the lever. The lower ends of the links 52 and 54 are connected through pivotal connections 56 and 58 to the forward end of the scraper bowl 10. A double-acting hydraulic jack 60 extends between the drawbar 12 and the lever 34 of the control mechanism and has the cylinder portion 62 thereof anchored to the drawbar by a pivotal connection 64, while the piston rod 66 is connected to the lever through a pivotal connection 68.

It will be noted that when the scraper bowl 10 is in the raised position, a portion of the lever 34 rests upon the troque tube 22, and, as a result, the bowl operating jack 60 is relieved from any load. In this regard and as explained heretofore, the links 52 and 54 connect the forward end of the scraper bowl 10 to the lever 34 and thus when the latter is in the bowl-carry position of FIGURE 2, the force vector representing the weight of the forward end of the bowl passes between the pivotal connections 42 and 68 thereby causing the lever to transfer such loading to the torque tube 22.

In order to lower the bowl 10 from the carry position to the dig position, the jack 60 is contracted resulting in the lever 34 rotating in a counterclockwise direction about the pivotal connection 42. During such movement, the pivotal connections 48 and 68 move to the left or forward side of a vertical line passing through the center of pivotal connection 42 as seen in FIGURE 2. This action causes the jack 60 to once again come under load due to the weight of the bowl.

It will be understood that there are an infinite number of positions that the bowl 10 can be located in between the fully raised position and the fully lowered position and that the hydraulic jack is only reliever from all loading when the pivotal connection 48 is located to the rear or to the right of the vertical line passing through pivotal connecion 42 as seen in FIGURE 2.

Variou changes and modifications can be made in this construction without departing from the spirit of the invention. Such changes and modifications are contemplated by the inventor and he does not wish to be limited except by the scope of the appended claims.

I claim:

1. A scraper having a tractor and a trailing bowl, a drawbar connecting the tractor with the bowl and supporting the latter for movement between a lowered-dig position and a raised-carry position, said drawbar comprising a transverse torque tube, a pair of rearwardly diverging structural members supported by the tractor and having the rear ends thereof rigidly secured to said torque tube, a pair of laterally spaced pull arms secured to the ends of the torque tube and extending rearwardly for pivotal connection with said bowl, a control mechanism including a duble-acting hydraulic cylinder supported by said drawbar for moving said bowl between said positions, said hydraulic cylinder having relatively movable piston and cylinder members, said control mechanism comprising a U-shaped lever including a pair of laterally spaced legs integrally formed with a transversely extending base section, a first pivotal connection supporting said legs on said torque tube for rotation about a transverse axis, a second pivotal connection on said lever located above the first pivotal connection when said bolw is in said lowereddig and raised-carry positions and connecting one end of said hydraulic cylinder to said base section, a third pivotal connection on said lever spaced from the first and second pivotal connections, and a link extending between the third pivotal connection and the forward end of the bowl for supporting the latter, said third pivotal connection being so located that the longitudinal center axis of the link crosses a portion of the piston member between the centers of the first and second pivotal connections and the base section of the lever is supported by the torque tube when the bowl is in a raised-carry position.

2. The scraper of claim 1 wherein the third pivotal connection is located above the first and second pivotal connections when the bowl is in the raised-carry position, and the third pivotal connection is located below the first and second pivotal connections when the bowl is in the lowered-dig position.

References Cited UNITED STATES PATENTS 617,430 1/1899 Warren 37l29 2,025,285 12/1935 Hunter et al 37129 2,308,193 1/1943 Miskin 37-l43 2,804,702 9/1957 Corser et al 37l26 EDGAR S. BURR, Primary Examiner US. Cl. X.R. 37l34 

